The invention relates to marine propulsion device shift apparatus, and, more particularly, to apparatus for shifting a reversible transmission in the lower gearcase of a marine propulsion device.
The prior art includes many such shift apparatus. Typically, a reversible transmission in the lower gearcase of a marine propulsion device includes a control member which is movable axially of the propeller shaft for actuating the transmission. The shift apparatus provides means for moving the control member axially in response to operator actuation of a remotely located control device.
An example of a prior art shift apparatus is disclosed is U.S. Hagen Pat. No. 3,919,964. Referring to FIG. 6, Hagen discloses a shift apparatus including a vertically movable actuating rod 57, a control member or shift actuator 51 movable axially of the propeller shaft, and means for moving the control member forwardly in response to downward movement of the actuating rod 57 and rearwardly in response to upward movement of the actuating rod 57.
When two marine propulsion devices are used on a single boat, it is preferable to have the propellers counter-rotating, i.e., rotating in opposite directions in the forward drive condition. Also, it is preferable to have shifting of the two marine propulsion devices controlled by a single remotely located control device. In order to have both counter-rotating propellers and a single control device it has previously been necessary for the two marine devices to have either different transmissions or different shift apparatus. For example, U.S. Taguchi Pat. No. 4,637,802 discloses four different arrangements for shifting identical transmissions in a pair of outboard motors with counter-rotating propellers. In each arrangement, the outboard motors have different shift apparatus, i.e., the shift apparatus are not identical. This necessitates manufacturing two different sets of parts.
Attention is directed to the following U.S. Patents:
______________________________________ U.S. Pat. No. ______________________________________ Armstrong 2,696,188 Dec. 7, 1954 Kloss 2,729,186 Jan. 3, 1956 Kloss 2,728,320 Dec. 27, 1955 Nakahama 4,527,441 Jul. 9, 1985 Iida 4,549,869 Oct. 29, 1985 Iio 4,579,204 Apr. 1, 1986 Taguchi 4,637,802 Jan. 20, 1987 ______________________________________